Recent UFC title challenger Thiago Santos is apparently a marvel of modern sports medicine – or perhaps lack thereof.

“Marreta” took light heavyweight champion Jon Jones to the limit in the main event of July 6’s UFC 239. The Brazilian slugger nearly dethroned the champion, only to ultimately lose by split decision. It was apparent Santos seriously injured his knee early in the bout as well. Many felt the outcome would have been much more skewed in Santos’ favor had he been able to fight at full capacity.

But it’s a wonder he was even able to fight at all. Santos tore every major ligament and his meniscus in his left knee during the fight. He underwent surgery on both of his knees earlier this week. Santos previously hurt his right knee prior to the Jones bout. The surgeries were successful, yet doctors are wondering how Santos fought in the first place.

In an interview with Portal do Vale Tudo, Santos revealed his doctor told him he shouldn’t have even been able to walk with his injuries, let alone fight:

“Every doctor that I saw asked me the same thing: ‘How were you able to fight like this?’. Tata (Duarte, Santos’ coach) asked a doctor: ‘Doc, is it normal for a person to be able to walk or even fight with a knee like that?’. The doctor told him: ‘No, it’s not. It was his mind, his mind took over. I have no scientific explanation.’”

It did appear that Santos was fighting on heart and heart alone in the latter rounds of his match-up with Jones. His knee repeatedly buckled but he still kept throwing kicks at Jones’ lead leg. Enough landed that the legendary champion had to be carried out of the Octagon by his cornermen.

The performance, even though it was a losing one, was truly an awe-inspiring display of courage. That’s only heightened due to this doctor’s view of the situation. Santos will reportedly be out of action for around eight months. It’s a very short timeline considering the extent of his injuries.

But then again, he fought one of the best fighters of all-time when he shouldn’t have even been able to walk.